Mohammed, P. A. H., and A. W. Kadhim Shubbar. “Evaluation of Triple Integrals With Continuous Integrands Numerically by Newton-Cotes Formulas”. Al-Qadisiyah Journal of Pure Science, Vol. 19, no. 1, July 2017, https://journalsc.qu.edu.iq/index.php/JOPS/article/view/113.